What are the 4 main triggers for mass movements?

What are the 4 main triggers for mass movements?

Factors that cause Mass Movements The factors that cause most mass movement events are the undercutting of steep slopes, the removal of vegetation, earthquakes, and heavy prolonged rainfall. Many mass movement disasters are preceded by development, deforestation, and slope steepening, which weakens the slopes.

What are the triggers of mass movements?

Mass-wasting events are triggered by changes that oversteepen slope angles and weaken slope stability, such as rapid snow melt, intense rainfall, earthquake shaking, volcanic eruption, storm waves, stream erosion, and human activities. Excessive precipitation is the most common trigger.

What are the 3 factors that cause mass movement?

Such factors include: weathering or erosional debris cover on slopes, which is usually liable to mass movement; the character and structure of rocks, such as resistant permeable beds prone to sliding because of underlying impermeable rocks; the removal of the vegetation cover, which increases the slope’s susceptibility …

What are five things that can trigger a mass movement?

Major Triggers for Mass Wasting: Water, Slopes, Vegetation Removal & Earthquakes.

How do humans affect mass movement?

Humans can contribute to mass wasting in a few different ways: Excavation of slope or its toe. Loading of slope or its crest. Drawdown (of reservoirs)

What is the slowest mass movement?

The slowest and least noticeable, but most widespread of the slow mass wasting categories is creep. Creep involves the entire hillside, and is characterized by very slow movement of soil or rock material over a period of several years.

What is fall in mass movement?

The basic types of landslide movement are: Fall. This is generally characterized by rapid or extremely rapid rate of movement with the descent of material characterized by a freefall period. Falls are commonly triggered by earthquakes or erosion processes.

What force must be overcome in order for mass wasting to occur in most cases?

For mass wasting to operate on a sloped surface the gravitational force must be resolved into two vectors (Figure 7). One must be the downward force acting perpendicular to the sloped surface. This is the “Stay Force” component of the vertical pull of gravity.

What are the fastest mass movements?

Rockfalls occur when rock fragments fall from steep cliffs. This is the fastest type of mass movement. The fragments may be as tiny as pebbles or as huge as giant boulders. Landslides occur when large amounts of loose rock combined with soil fall suddenly down a slope.

What are other factors that can trigger mass movements?

Other factors that can trigger mass movements include saturation of surface materials with water, oversteepening of slopes, removal of vegetation, and earthquakes What is the force behind mass movements?

What causes a mass movement in the Earth?

Rivers can erode the base of a slope and cause a mass movement. Heavy rain and earthquakes can also trigger a mass movement.

Is there such thing as a slow mass movement?

Creep is a very slow mass movement that goes on for years or even centuries. You can’t see creep happening but leaning fences and poles and broken retaining walls show where it has taken place.

What are the different types of mass movements?

Types of mass movement Mass movements can be divided into four main classes. These are falls, slides, creeps and flows. The classes are based on how quickly the rock and sediment moves and how much water there is.